Conventionally, for example, a motor type damper device for controlling the taking of cold air in a refrigerator has been known as a motor unit (motor actuator) in which a motor such as an AC synchronous motor or a stepping motor is used as a drive source (see, for example, Japanese Patent Laid-Open No. Hei 6-109354).
In the case of the motor type damper device which is disclosed in the above-mentioned Japanese Patent Laid-Open No. Hei 6-109354, a baffle and a drive mechanism part such as a motor are disposed across a rotary fulcrum shaft. When the motor is rotated in one direction to move a rack upward, an engaging shaft abuts with an upper face of a hollow portion to turn the baffle in an open direction and thus an intake opening for cold air is opened. Further, when the motor is rotated in the other direction, a lower portion of the engaging shaft abuts with the elastic piece of an elastic plate and depresses it downward to turn the baffle in a close direction.